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Polyanhydrides, 5. Thermotropic poly(ester anhydrides) derived from monoalkylthioterephthalic acids, hydroquinone and 4‐hydroxybenzoic acid
Author(s) -
Kricheldorf Hans R.,
Domschke Angelika
Publication year - 1994
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1994.021950311
Subject(s) - thermotropic crystal , differential scanning calorimetry , chemistry , polymer chemistry , side chain , condensation polymer , alkyl , hydroquinone , magic angle spinning , hydroxybenzoic acid , nuclear magnetic resonance spectroscopy , organic chemistry , polymer , liquid crystalline , physics , thermodynamics
Monoalkylthioterephthalic acids and their acyl chlorides were prepared via nucleophilic substitution of diethylbromo‐ or diethyl chloroterephthalate with thiols. Various poly(ester anhydrides) were synthesized by polycondensation of alkylthioterephthaloyl chloride with silylated 4‐hydroxybenzoic acid and silylated hydroquinone. The resulting poly(ester anhydrides) were characterized by elemental analyses, inherent viscosities, IR spectroscopy, differential scanning calorimetry (DSC) and wide‐angle X‐ray scattering (WAXS) measurements, optical microscopy and 13 C NMR cross polarization/magic angle spinning (CP/MAS) spectroscopy. For the chain packing of these monosubstituted poly(ester anhydrides) a sanidic type of layer structure with a “back‐to‐back array” of the main chains is proposed. The alkyl side chains form ordered domains with predominantly all‐ trans conformations. In most cases, three endotherms are observable in the DSC heating traces corresponding to the melting of the side chains and to reversible transitions into two different liquid‐crystalline phases.